Fix ARM & ARM64 UnsafeGetObject intrinsics with read barriers.

The implementation was incorrectly interpreting the 'offset'
input as an index in a (4-byte) object reference array,
whereas it is a (1-byte) offset to an object reference field
within the 'base' (object) input.

Bug: 29516905
Change-Id: I4da5be0193217965f25e5d141c242592dea6ffe8
Test: Covered by test/004-UnsafeTest.
diff --git a/compiler/optimizing/intrinsics_arm64.cc b/compiler/optimizing/intrinsics_arm64.cc
index c8d6ddc..12d65be 100644
--- a/compiler/optimizing/intrinsics_arm64.cc
+++ b/compiler/optimizing/intrinsics_arm64.cc
@@ -791,8 +791,15 @@
     // UnsafeGetObject/UnsafeGetObjectVolatile with Baker's read barrier case.
     UseScratchRegisterScope temps(masm);
     Register temp = temps.AcquireW();
-    codegen->GenerateArrayLoadWithBakerReadBarrier(
-        invoke, trg_loc, base, 0U, offset_loc, temp, /* needs_null_check */ false);
+    codegen->GenerateReferenceLoadWithBakerReadBarrier(invoke,
+                                                       trg_loc,
+                                                       base,
+                                                       /* offset */ 0U,
+                                                       /* index */ offset_loc,
+                                                       /* scale_factor */ 0U,
+                                                       temp,
+                                                       /* needs_null_check */ false,
+                                                       is_volatile);
   } else {
     // Other cases.
     MemOperand mem_op(base.X(), offset);
@@ -821,7 +828,8 @@
   locations->SetInAt(0, Location::NoLocation());        // Unused receiver.
   locations->SetInAt(1, Location::RequiresRegister());
   locations->SetInAt(2, Location::RequiresRegister());
-  locations->SetOut(Location::RequiresRegister(), Location::kNoOutputOverlap);
+  locations->SetOut(Location::RequiresRegister(),
+                    can_call ? Location::kOutputOverlap : Location::kNoOutputOverlap);
 }
 
 void IntrinsicLocationsBuilderARM64::VisitUnsafeGet(HInvoke* invoke) {